Thickness and strain dependence of piezoelectric coefficient in thin films
- Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Center for Nanophase Materials Science (CNMS)
- Pennsylvania State Univ., University Park, PA (United States)
- Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
We explore the thickness dependence of the converse piezoelectric coefficient (d33) in epitaxial thin films of BaTiO3 (BTO) grown on (001) SrTiO3 substrates. Piezoresponse force microscope was performed using an atomic force microscope equipped with an interferometric displacement sensor allowing direct quantification of electromechanical coupling coefficients in BTO free from unwanted background contributions. We find that 80-nm-thick films exhibit a d33 of ~20.5pm/V, but as the thickness is reduced, the d33 reduces to less than 2 pm/V for a 10 nm film. To explain the atomistic origin of the effect, we performed molecular dynamics simulations with a recently developed ab initio-derived reactive force field, constructed using the ReaxFF framework. Simulations predict that under applied electric fields thin films of BaTiO3 show an increasing thickness, with compressive strain, of the region screening the depolarization-field. This study confirms quantitatively the drop in piezoelectric performance in BTO ultrathin films and again highlights the importance of the screening mechanisms when films approach the ultrathin limits in dictating the functional behaviors.
- Research Organization:
- Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States). Center for Nanophase Materials Sciences (CNMS); Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States). National Energy Research Scientific Computing Center (NERSC)
- Sponsoring Organization:
- USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22). Materials Sciences & Engineering Division; US Air Force Office of Scientific Research (AFOSR)
- Grant/Contract Number:
- AC05-00OR22725; AC02-05CH11231; AFRL FA9451-16-1-0041; FA9550-19-1-0008; AC0500OR22725
- OSTI ID:
- 1599490
- Alternate ID(s):
- OSTI ID: 1606934
- Journal Information:
- Physical Review Materials, Vol. 4, Issue 2; ISSN 2475-9953
- Publisher:
- American Physical Society (APS)Copyright Statement
- Country of Publication:
- United States
- Language:
- English
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